Benfabriken



U ITE ST -Ins "PATENT OFFICE.

.WILLIAM PFITZINGER, .OF ELBERFEIJD, GERMANY, ASSIGNOR TO THE FAR- BENFAB RIKEN, VORMALS FR. BAYER'& (10., OF SAME PLACE.

PROCESS OF DYEING BLACK.

I SPECIFICATION forming m of Letters Patent No. 501,160, dated July 11, 1893.

Application filed November 19,1891. $erial No. 412,438. (No specimens.) Patented in Germany April 1, 1890, No. 53.799; in

England June 2, 1890 No. 8,530; in Belgium October 29, 1890, No. 92,5l7iin Italy January 31, 1891, XXV, 29.122, and in I Austria-Hungary January 23, 1891, No. 4,929 and No. 22,349.

To all whom it may concern:

Be it known that I, WILLIAM PFITZINGER, chemist, (assignor to the FARBENFABRIKEN,

' VORMALS FR. BAYER 8: 00., of Elberfeld,) a

subject of the Emperor of Germany, residing at Elberfeld, Germany, have invented a new and useful Improvement in Producing Black Az'o Dyes on Fiber, (for which the aforesaid FARBENFABRIKEN has already obtained Letters Patent in Germany, No. 53,799, dated April 1, 1890; in England, No. 8,530, dated June 2, 1890; in Austria-Hungary, No. 4,929 and No. 22,849, dated January 23, 1891; in' Italy, XXV, No. 29,122, dated January 31, 1891, and in Belgium, No. 92,517, dated October 29, 1890,) of which I give in the following a clear and exact description.

' My invention relates to the production of black azo dyes on the fiber and depends on a peculiar property of coloring matters which are obtained by combining one molecular proportion of tetrazodiphenyl, or as equivalents therefor in this process tetrazoditholyl, tetrazomethoxydiphenyl, tetrazoethoxydiphenyl, tetrazodiphenoldi methyl ether, tetrazodiphenoldiethylether or tetrazostilbene either with two molecular proportions of amidonaphtholmonosulfo acid G or as equivalents therefor in this process of the amidonaphtholdisulfo acid formed by melting with alkalies the alphanaphthylamine trisulfo acid which results when the nitro compound of the naphthalenetrisulfo acid described in the German Patent No. 38,281, dated September 2, 1885, is reduced, or as equivalents therefor in this process with one molecular proportion of any of the two aforesaid amidonaphthosulfo acids and with one molecular proportion of a phenol, or as equivalents therefor in this process a naphthol or the sulfo and carboxylic acid of aphenol or naphthol or naphthylamine or the sulfo acid thereof. The last named dye-stulfs, when fixed on fiber, are capable of being diazotized and the thus produced diazo compounds of the aforesaid coloring matters may directly be combined on fiber with phenols or as equivalents thereforin this process with naphthols, amines, amid ophenols or amidonaphthols, di-

hydroxynaphthalenes or the sulfo acids of these compounds.

In carrying out my process practically I proceed as follows: About ten kilos, by weight,

of unmordanted cotton are at first colored in a boiling bath prepared by dissolving in two hundred liters of water about one kilo of common salt and 0.6 kilos of the dye-stuff which is for example resulting by the combination of one molecular proportion of tetrazodiphenyl chlorid with two molecular proportions of amidonaphtholmonosulfo acid G; thereupon the cotton after having been washed with water is introduced into a solution of one kilo of sodium nitrate in two hundred liters of cold water on addition of two kilos of muriatic acid (20 Baum). In this manner there is formed the diazo compound which likewise remains fixed on the fiber and is fast to washing to which the cotton after its re moval out of the solution of sodium nitrate by preference is to be subjected. By introducing the cotton thus prepared into an alkaline solution of about 4.5 kilos of beta naphthol the formation of the dye-stud takes place on the fiber and the end of this reaction may easily be recognized as the cotton gradually assumes a deep bluish-black color while that produced on it by the said diazo compound is a pure blue-black. When the intensity of the color does no more increase the cotton is carefully washed with water; it shows after the treatment described a deep bluish-black, which is very fast to alkalies and acids and which as to its intensity, brightness and beauty surpasses by far the shades produced by the coloring matter derived from one molecule of tetrazodiphenyl chlorid and two molecules of amidonaphtholmonosulfo acidG. The shades which are produced when on the fiber the coloring matter formed from one molecule of tetrazodiphenyl chloridand two molecules of amidonaphtholmonosulfo acid G is diazotized and combined with betanaphthol especially differ by their absolute fastness to soaping from those which result when the said tetrazo dyestuff is employed without being further diazotized and combined with betanaphthol.

According to this process many reactions may be carried out in a very simple way and directly on the fiber. A great Variety of black shades with reddish, bluish or violet tones results as on the one hand the tetrazodiphenyl chlorid may be replaced with the similar result by the analogous compounds: tetrazoditolyl chlorid, tetrazomethoxydiphenyl chlorid, tetrazoethoxydiphenyl chlorid,tetrazodiphenoldimethylether,tetrazodiphenoldiethylether or tetrazostilbene and as on the other hand instead of betanaphthol there may be employed also alphanaphthol, the sulfo and carboxylic acids of both, dihydroxnaphthalenes or their snlfo acids, alphaand betanaphthylamine or their sulfo acids, phenol, resorcine, salicylic acid, metaphenylene diamnaphtholethers, amidonaphtholsulfo acids in what manner the same is to be performed, that which I claim as new, and desire to secure by Letters Patent, is-- The process of dyeing cotton, which consists, first, in dyeing said cotton by a coloring matter such as is obtained by the combination of one molecule of tetrazo diphenyl or analogous compounds thereof with two molecules of amido naphthol monosulfo acid G; second, in diazotizing on the fiber the dyestufi thereon which contains one or two free amido groups; and, third, combining the resulting diazo compound with phenol, substantially as described.

In testimony whereof I have signed my name in the presence of two subscribing wit- WILLIAM PFITZINGER.

nesses. ine, chrysoidlne,amldonaphthols and amido- Witn esses:

WM. ESSENWEIN, RUDODPH FRICKE.

It ishereby certified that in Letters Patent No. 501,160, granted J my 11., 1893, upon the application of William Pfitzinger, of Elberfeld, Germany, for an improvement in Processes of Dyeing Black, errors appear in the printed specification requiring the following correction, viz: In lines 64 and 70, page 1, the word nitrate should read nitrite and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the casein the Patent Office. Signed, countersigned, and sealed this 1st day of August, A. D. 1893. i I

[SEALJ .r JNO. M. REYNOLDS,

Assistant Secretary of the Interior. Gountersigned JOHN S. SEYMOUR,

Commissioner of Patents. 

